Electric hot-plate or heat unit.



1. c. PATTEN. ELECTRIC HOT PLATE OR HEAT UNIT. APPLICATION FILED AUG.30. I9I5. 1,233,395, Patented July 17, 1917.

2 SHEETS-SHEET I.

1.*C. PATTEN.

- ELECTRIC HOT PLATE OR HEAT UNIT.

APPLICATION FILED AUG. 30, 1915. 1,233,395. l Patented Ju1y1I,1917.l

2 SHEETS-SHEET 2.

A TTOR/VEYS following specification.

STATES PATENT 4omnes.

` IL HES C. PATTN, F KKOIO, INDIANA, ASSIGNOB T0 .THE-GLGBE STO'V'E &:RANGE coikrm, or xoxoxo, INDIANA. Y

`:minerais nominare on mr UNIT.

Application led August 80, 1915. Serial'loAS'?.

To all 'whom 'it may concern;

Be it known that I, JAMES C. PATTEN, a citizen of the United States,residing at Kokomo Indiana, have invented certain new and useful Imrovements in Electric Hot- Plates or Heat Il'nits, of which thefollowing is a specification.

This invention relates to improvements in electric hot plates or heatunits.

The objects of the invention are:

First, to increase the capacity of such a unit in delivering the radiantheat therefrom.

Second, to increase the durability o f the coils of wire, particularlyat the terminals.

Third, to secure effective connections and avoid arcing.

. details and economies of construction and operation will definitelappear from the detailed description to ollow.

- I accomplish the objects of my invention by the .devices and meansdescribed in the The invention is clearly defined and pointed out in theclaims.

A structure which is a preferred embodiment of my invention is fullyillustrated in the accompanying drawing, forming a part of thisspecication, in which:

Figure I is a plan view of a hot plate embodyinglthe features of myinvention.

Fi groovged porcelain plate holding the heating coils.

Fig. III is a detail sectional view on line 3-3 of Fig. I, showing myimproved heater supported on the base.

Fig. IV is a detail sectional view on line 4-4 of Fig. I, showing thedetails of the terminal pins and their connections.

Fig. V is an enlarged detail plan view of terminals of thestructureappearing in Fig. I, showing the details of the coilng andarrangement of the wires at the terminals.

Fig. VI is an enlarged detail sectional view on line 6 6 of Fig. V,showing the flattening of the wires at the terminals and the method ofsecurin the same.

Fig. VII is an e arged detail sectional l View showing .the method ofsecuring the coil in another form of heat unit in which my invention maybe made use of.

In the drawings the sectional views are taken looking in the directionof the little arrows at the ends of the section lines and I is a planview ofthe detachedV BpeaMloat-ion of Letters Patent. l Patented J Illy17, 1917..

' an insulating material 2, such as fiber or asbestos. `An insulatorplate 3 of porcelain is provided for supporting the heating coilsanda'metal plate 4 to shield and protect the same 1s provided and held inplace by screws 5 through said plates and through slotted Aopenings 6 inthe said porcelain plate. Coils 7 are disposed in the bottoms of thegrooves 7 in said porcelain plate. The coils are flattened so that eachturn ofthe coil is'substantially an ellipse and each coil is connectedto a terminal pin 8, all of these parts being similar in design to thatappearing in the concurrent patent application of Maurice E. Louth andJess Jackson.

I connect the coils to the terminal pins by, forming a loop 12 in theends thereof, which is clamped between the bindingl nuts 9 and 10 (seeFig. VI). A Washer 11 is disposed between these to improve the contact,and the loop l2 of the coil preferably has the wire iiattened to make abroad contact at this point. The end 13 of the wire is Wound in a loosecoil around the main part of the wire 7 and the coils of wire at thisplace are opened out as seen at 14. in Figs. V and VII. The object ofthis is that the conductivity of the 'wire is increased by doubling thesame and by wrapping the Wire therearound, and the temperature of thepart at this point is reduced by the lessened resistance and the greatermass of metal and by opening out the coil, so that there is no abruptshoulder where the high temperature begins and consequently noparticular spot where the coil or wire is injuriously affected by suchhigh temperature. I find that by this arrangement the terminals lastsubstantially as long as the coils themselves, whereas without tliesemeans the terminals very quickly burn o I also avoid arcing by using analloy forl the binding post parts with a very low coefficient ofexpansion, finding that an alloy can be made use'of that has about thesame expansion as platinum, and by making use of the same and with thebroad surface of the fiattened wire a perfect contact is secured so thatthere is no Aarcing at these points. The particular metal used is known

